Polyvinyl acetal resin compositions containing trimethylene glycol ditetrahydrofuroate



Patented Sept. 3, 1940 PoLrvrNYi. AGETAL nnsm COMPOSITIONS GONTAININ G TRIMETHYLENE GLYCOL DITETRAHYDROFUROATE I Henry B. Smith, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application December 14, 1938, Serial No. 245,707

9 Claims.

This invention relates to plastic compositions, and more particularly to compositions comprising a. polyvinyl acetal resin and a conditioning agent.

5 One object of this invention is to produce compositions of matter which may be made into permanently transparent, strong and flexiblle sheets or films of desired thinness which are substantially waterproof, are unaffected by ordinary photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of my invention is to produce compositions of matter which can be made into sheets suitable for use in laminated, shatter-proof glass. Still another object is to produce compositions which can be rolled, extruded, molded or otherwise worked into relatively thick sheets and massive plastics. A further object is to produce compositions suitable for use in lacquers, artificial silk filaments, wrapping tissues and the like. Other objects will hereinafter appear.

I have discovered that trimethylene glycol ditetrahydrofuroate is a useful conditioning agent for polyvinyl acetal resins. Not only does it serve as a plasticizer in the accepted sense of the term, increasing the flexibility and toughness of polyvinyl acetal resin films, sheets, or other objects or masses containing it, but when used in amounts of about 40 or more parts per 100 parts of certain of the polyvinyl acetal resins, namely the polyvinyl acetal resins in which a predominating proportion of the acetal groups are butyraldehyde acetal groups, it has an unusual and r, remarkable effect which I may call elasticizing.

That is to say, a sheet of a polyvinyl butyraldehyde acetal resin containing about 40 or more parts of trimethylene glycol ditetrahydrofuroate per 100 parts of resin possesses the property 40 which, in the rubber industry, is known as nerve: namely, the property of stretching to a considerable extent when tension is exerted upon it, and returning to its original dimensions when the tension is released. This property renders such sheets, which I shall call rubbery sheets, particularly useful in the manufacture of shatter-proof glass.

For the manufacture of cast films or sheets, the polyvinyl acetal resin and trimethylene glycol ditetrahydrofuroate may be dissolved in a suitable solvent or solvent mixture, such, for instance, as acetone,. methanol, acetone-methanol mixtures, ethylene chloride-methanol mixtures, etc., about 300 to 500 or more parts of the solvent or solvent mixture being used per 100 parts of the ate per 100 parts of resin may be employed, depending upon the nature of theresin and the purpose for which the sheets are to be used. Suitable proportions of trimethylene glycol ditetrahydrofuroate for any resin and any purpose may be readily determined by experiment. For the manufacture of sheets suitable for photographic filmbase, from 5 to 25 parts of trimethylene glycol ditetrahydrofuroate per 100 parts of resin are suitable. The resin solution is cast as a sheet, the solvent evaporated, and the sheet stripped from the casting surface.

Sheets for use in laminated glass may be formedby casting, or may be made without the use of volatile solvent by extrusion, for example in the manner set forth in application Serial No. 147,934 of John S. Kimble and Ernest C. Blackard, filed June 12, 1937. For instance, 40 or more parts of trimethylene glycol ditetrahydrofuroate and 100 parts of a polyvinyl butyraldehyde acetal resin may be mixed in a suitable, jacketed mixer, at a low temperature, for example 10 C., and the mixture may then be worked on hot rolls, in the manner described in U. S. Patent 2,048,686 of F. R. Conklin, until complete homogenization has taken place. The mass thus produced may then be extruded through'an annular die, and the tube so formed slit to form a sheet.

The polyvinyl acetal resins can be prepared by reacting polyvinyl alcohol with an aldehyde in the presence of an acetal condensation catalyst, e. g. a mineral acid. These resins can also be prepared by simultaneously de-esterifying a polyvinyl aliphatic ester and reacting the deesterification product with an aldehyde in the presence of a de-esterifying catalyst and acetal condensation catalyst. Mineral acidsare catalysts for both de-esterification and acetal formation. Among the polyvinyl acetal resins with which trimethylene glycol ditetrahydrofuroate is useful may be mentioned, as illustrative examples, the polyvinyl formaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins, the polyvinyl formaldehyde acetaldehyde mixed acetal resins, the polyvinyl butyraldehyde acetal resins, and the polyvinyl butyraldehyde acetaldehyde mixed acetal resins.

Examples of the preparation of polyvinyl formaldehyde acetal resins may be found in U. S. Patent 1,955,068, Examples 1, 4 and 5; in U. S. Patent 2,036,092, Examples 1, 2, 3, '7 and 8; in British Patent 454,691, Examples 1, 2, 3, 4, 5,

H resin. From about 5 to 100 parts or more of trimethylene glycol ditetrahydrofurm 6 and 7; in British Patent 404,279, Example 3; and in'British Patent 486,072, Examples 1, 2, 3, 4, 5,6and7.

Examples of the preparation of polyvinyl acetaldehydeacetal resins may be found in U. 8. Patent 2,044,730, Example 1; U. 8. Patent 1,955,068, Example 2; U. 8. Patent 2,036,092, Examples 4. 5 and 6 British Patent 466,598, Examples 1, 2, 3, 4 and 7; British Patent 404,279, Examples 1, 2, 4, 5, 6, 7 and 8;- U. S. Patent 1,990,399; and French Patent 808,578, Examples 1, 2 and 3. An additional example of the preparation of a polyvinyl acetaldehyde acetal resin is as follows:

'50 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in a mixture composed of 50 lbs. of 95% ethyl alcohol and 90 lbs. of ethyl acetate. To this solution was-added 19.2 lbs. oi paraldehyde. Then a catalyst consisting of 5 lbs. of 95% sulfuric acid diluted with 5 lbs. of water was added. After thorough mixing, the reaction was allowed.- to proceed at 40 C. for 8 days. The reaction mixture was then diluted with acetone, and the resin precipitated by pouring into cold water, washed and dried. Analysis showed the resin to have an acetate group content equivalent to 3.3% of polyvinyl acetate and a hydroxyl formaldehyde were placed in an enamelled vessel and brought into solution by stirring. When solution was complete, 10 parts of sulfuric acid group content equivalent to 6.5% of polyvinyl alcohol.

Examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins may be found in British Patent 430,136, Examples 1, 2, 3, 4, 5 and 6; British Patent 445,565, Example 2;

British Patent 465,873, Examples 1, 2, 3, 4, 5 and- 6; French Patent 808,586, Examples 1, 2, 3, 4, 5, 6,

1 12, 13, 14, 15, 16, 17, 18 and 19. Additional examples of the preparation of polyvinyl formaldeihyde acetaldehyde mixed acetal resins are as follows:

100 parts (1.16 mole calculated as monomeric vinyl acetate) of a polyvinyl acetate (45 centipoises), 100 parts of ethyl alcohol, 180 parts of ethyl acetate, 34 parts (.77 mole as monomeric acetaldehyde) of paracetaldehyde and 5.8 parts (.196 mole as monomeric formaldehyde) of para- (5}). gr. 1.84) in 10 parts of water was added, and the mixture stirred. The mixture was maintained at a temperature of 40 C. for 144 hours. The contents of the vessel were then diluted with about-two and a half volumes of acetone, and the mixture precipitated by pouring into water. The precipitated resin was washed free from impurities by repeated changes of cold water, and dried. The resin, when analyzed, gave a hydroxyl group content equivalent to about 6.4 per cent by weight of polyvinyl alcohol, an acetate group content equivalent to about 4.0 per cent by weight of polyvinyl acetate, a formaldehyde acetal group content equivalent to about 15.9 per cent by weight of polyvinyl formaldehyde acetal and an acetaldehyde acetal group, content equivalent to about 73.9 per cent by weight of polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made up of about 19.7 per cent by moles of polyvinyl formaldehyde acetal and about 80.3 per cent by moles of polyvinyl acetaldehyde acetal. The resin was soluble in acetone to an extent which permitted coating a film or sheet from the resin.

50 parts (.58 mole as monomer) of polyvinyl acetate (45 centipoises) 50 parts of ethyl alcohol, parts of ethyl acetate, 17 parts (.385 mole as monomer) ofparacetaldehyde, 2.9 parts (.098 mole as monomer) of paraformaldehyde', 5 parts :of sulfuric acid and 5 parts of water were treated hyde acetal group contentequivalent to about 69.9 per cent of polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made up of about 18.5 per cent by moles of polyvinyl formaldehyde acetal and 81.5 per cent by moles of polyvinyl acetaldehyde acetal. The resin was soluble in'acetone to an extent which permittedcoating a film or sheet from the resin.

1300 parts (15.1 mole as monomer) of a polyvinyl acetate (45 centipoises) 1700 parts of ethyl acetate, 2250 parts of ethyl alcohol and 48 parts (1.57 mole as monomer) of paraformaldbhyde (trioxymethylene) were placed in a vessel equipped with a reflux condenser and a means of agitation, and the contents brought to a temperature of about 70 C. by means of steam heating. 182.25 parts of sulfuric acid (sp. 'gr. 1.84) dissolved in 51.5 parts of water were added, and the whole was heated at about 70 C. for about five hours, agitating throughout. At this point, 266.4 parts (6.05 mole as monomer) of paracetaldehyde were added, and heating at about 70 C. with agitation was continued for a further period of twenty hours. The contents of the reaction vessel were neutralized with ammonium hydroxide and diluted with water precipitating the resin as a cake. The cake was cut into small pieces and repeatedly washed with hot and other impurities. The resin, upon analysis, showed a hydroxyl group content equivalent to about 10.1 per cent by weight of polyvinyl alcohol, an acetate group content equivalent to about 32 per cent by weight of polyvinyl acetate, the remainder of the weight of the resin being polyvinyl acetal. The polyvinyl acetal portion of the resin was made up of about 80 per cent by moles of polyvinyl acetaldehyde acetal and about 20 per cent by moles of polyvinyl formaldehyde acetal. The resin was not quite soluble in acetone, but could be made to dissolve by admixing small amounts of other solvents, such as alcohols, with the acetone.

Examples of the preparation of polyvinyl butyraldehyde acetal resins may be found in U. 8. Patent 2,044,730, Examples 2, 5 and 6; British Patent 466,598, Example 5; French Patent 813,- 303, Example 1; French Patent 813,514, Examples 1, 2, 3 and 4; and British Patent 459,878, Examples 1, 2, 5, 6, 7, 8, 9 and 10. An additional example of the preparation of a polyvinyl butyraldehyde acetal resin is as follows:

20 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 20 lbs. of 95% ethyl alcohol and 36 lbs. of ethyl acetate. To this solution was added 13 lbs. of butyraldehyde and a solution of 2 lbs. of sulfuric acid in 2 lbs. of water.

tent equivalent to 7.8% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 4.8% by weight of polyvinyl alcohol.

An example of the preparation of a polyvinyl butyraldehyde acetaldehyde mixed acetal resin is given in French Patent 813,303, Example 2.

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1. A composition of matter comprising a polyvinyl acetal resin and trimethylene glycol ditetrahydrofuroate as a. plasticizer therefor.

2. A transparent flexible sheet comprising 100 parts of a polyvinyl acetal resin and 5 to 25 parts, approximately, of trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

3. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetal resin in which a predominating proportion of the acetal groups are butyraldehyde acetal groups, and at least 40 parts, approximately, of trimethylene glycol ditetrahydrofuroate as an elasticizer therefor.

4. A composition of matter comprising a polyvinyl acetaldehyde acetal resin and trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

5. A transparent, flexible sheet comprising 100 parts of a polyvinyl acetaldehyde acetal resin and from 5 to 25 parts, approximately, of trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

6. A composition of matter comprising a polyvinyl formaldehyde acetal resin and trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

'7. A transparent, flexible sheet comprising 100 parts of a polyvinyl formaldehyde acetal resin and from 5 to 25 parts, approximately, of trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

8. A composition of matter comprising a polyvinyl butyraldehyde acetal resin and trimethylene glycol ditetrahydrofuroate as a plasticizer therefor.

9. A transparent, rubbery sheet comprising 100 parts of a polyvinyl butyraldehyde acetal resin and at least 40 parts, approximately, of trimethylene glycol ditetrahydrofuroate as an elasticizer therefor.

HENRY B. SMITH. 

